Calculator.



c. H; DUFFY. CALCULATOR.

APPLICATION FILED MARI9. 1915-.4

Patentedv Nov. 23, 1915.

COLUMBIA PLANouR/PH fo., wAsHlNuTuN. D. C.

-U'Nirnn sTATEs" rATENT onirica.

CHARLES HUGH-DUFFY, OF CHEVY CHASE, MARYLAND.

To all 'whom it may concern lBe it known that I, CHARLES HUGH DUFFY, acitizen of the United-States, re-

siding lat Chevy Chase, in the county ofV Montgomery and StatevofMaryland, haveA invented certainrnewand useful Improvements inCalculators; and I do declare the following to be'a full, clear, andeXact devio scription ofthe invention, such as will enable othersskilled in the art to which it appertains toY make and use thehsame,reference being had to the accompanying drawings, and 4to the lettersand-figuresof ref-v erence markedthereom `which form a part of thisspecification.

This invention relates-to the class of calculators but more particularlyto a device for adding, subtracting, dividing and multiplying twofigures, the same'beingk arranged in such manner that the sum, the

' difference, the result` and the quotient of the addition, subtraction,multiplication and division of two numbers will be simultaneouslyindicated. Y Y c -The invention consists in the arrangement of twodisksl pivoted centrally so as to be Y capable. of relative rotation,the under disk having thereon marginal numbers spaced one from the otherrand having opposite each marginal number the sums, the differences, theresults and the quotients of said number and any other marginal numberappearing on the upper disk, the said upper ldisk being provided withmarginal numbers VLike numerals of'reference indicate the same partsthroughout the three figures.

For a morey ready and simple illustration of this invention the deviceillustrated in the accompanying drawing has been limited to Figs. l to5, as the same is clearly sufficient to illustrate the construction andprinciple ofthe invention `and any additional iigureswould undulycomplicate they illusrSpecification of Le'ttersrPatent.

CALCULATOR.

Patented Nov. 23, 1915.

Application filed March 9, 1915.; Serial No. 13,175.

tration,yandj would add nothing to a clear -1 understanding of theinvention. it is-.to be clearly understood that the marginal numbers onthe disks can run from l to Aanydesired number, the only limit beingAlthough i the size of the disks, and inY practice it is desired toinclude on the disks marginal numbersrunning higher than those shown linthe accompanying drawing.

Referring to the drawing by reference numerals 1 indicates the devicecomprising the lower disk 2 and the upper disk 3f pivoted centrally at 4in the manner as shown in F ig, 3.l The lower disk.2 is preferablylargerl in diameter than the upper disk 8, sol that the largeVmarginalnumbers 'may be displayed thereon, although this constructionis not entirely essential as the marginal numbers 5 on the lower diskmay be placedimmediately around the pivotal point thereof, while themarginal numbers 6 on c theupper disk may be similarly disposed.

Vadjacent the pivotal point.

c In this event thetwo disks 2 and 3 could be of equal diameter. Fromthis it will be understood that the marginal numbers hereinbefore andhereinafter mentioned may be disposed on the disks in the mostconvenient manner,

so long Aas they are visible and can be brought opposite.

The disk2 having the marginal numbers 5 is preferably provided withk aseries yof marks 7 while the upper disk 3 is preferably provided withv aseries of marks 8,-

whicli marks on said disks Vshould register in the manner as shown inFig. l inorder to insure the proper position of the upper disk inrelation to the" lower disk when any of the marginal numbers on the saiddisks are brought opposite to each other for the puri' pose ofindicating the sum, the difference, the result and the quotient of thesaid two numbers, saidseries of numbers being indicated by the numeral5.

The marginal numbers on. the upper disk are preferably providedwith theusual arithmetical signs .9 and the equal marks 10 and lines 11 passingtherefrom to the openings 12 in the disk 3, so that the numbers on thelower disk visible through the openings l2 are quickly connected by theeye with the marginal numbers on the upper disk lin the manner asillustrated in Fig. l.

Having thus described the invention it will be noted `from Fig. l thatthe openings 12 on the disk 3 are differently located in said disk foreach marginal number thereon, said openings on said upper diskcorresponding with the numbers appearing on the lower disk which are thesums, the differences, the results and the quotients of any of saidmarginal numbers on the lower disk with respect to any and all of thesaid numbers on the said upper disk in such manner that the openings onthe said upper disk which are opposite a certain marginal number thereonwill always uncover certain numbers on the lower disk arranged at acertain predetermined point on the lower disk, in the manner as will beclearly apparent upon inspection of the accompanying drawing.

I lay no claim whatever to a calculating device in which only a singlefactor of two given numbers is indicated or uncovered by the calculator,as such a device is not within the spirit of this invention, which isprimarily designed as a mathematical educational device wherein aplurality of factors of two given numbers are simultaneously displayedor indicated.

Having thus fully described the invention what I claim as new and desireto secure by Letters Patent of the United States is l. A calculator ofthe type described including two relatively rotatablel disks centrallypivoted, the lower disk containing a series of marginal numbers, theupper disk containing a series of marginal numbers, the lower diskcontaining opposite each marginal number thereof the sums, thedifferences, the products and the quotients of said marginal number withrespect to every marginal number appearing on the upper disk, the saidupper disk being provided with an opening opposite each marginal numberthereon and in line with the numbers on the lower disk constituting thesum, the differ ence, the product and the quotient of said marginalnumber on the upper disk with respect to a marginal number on the lowerdisk, to simultaneously indicate the sum, the dilference, the productand the quotient of any two marginal numbers upon a single relativemovement 0f the disks, the said opening opposite each marginal number onthe upper disk being disposed in a different position from the otheropenings therein substantially as described and for the purposes setforth.

2. A calculator of the character described including a lower disk havingmarginal numbers thereon, an upper disk pivoted thereto and having'marginal numbers thereon, the lower disk being provided opposite eachmarginal number thereon with a plurality of series of numbers, the samebeing the factors of said marginal number with respect to all of themarginal numbers on the Lipper' disk, the said upper disk being providedwith an opening opposite each marginal number thereon and in line withthe numbers on the lower disk corresponding with the factors of saidmarginal number in connection with all of the marginal nun1- bers on thelower disk to simultaneously uncover a number of each plurality ofseries of numbers on the lower disk opposite a marginal number thereonupon a single relative movement of the disks, the said opening in saidupper disk opposite each marginal number thereon being disposed in saidupper disk at a diiferent point from the other openings thereinsubstantially as described.

3. A calculator' of the character described including a lower disk andan upper disk pivoted together, each of said disks being provided withmarginal numbers adapted t0 be brought opposite to each other uponrelative rotation of the said disks, the said lower disk containingopposite each marginal number thereon a plurality of series of numbers,each series of numbers being the results or factors of said marginalnumber in connection with all of the marginal numbers on the ripperdisk, the said upper disk being provided with an opening thereinopposite each marginal number thereon to uncover a numer in each of saidplurality of series of numbers opposite each of the marginal numbers onsaid lower disk to simultaneously indicate a plurality of results orfactors of any marginal. number on the upper disk in connection with anymarginal number on the lower disk upon a single relative movement of thedisks, substantially as described and for the purposes set forth.

In testimony whereof, I afx my signature, in presence of two witnesses.

CHARLES HUGH DUFFY. l/Vitnesses:

REID STANTON, MARGARET SHAW.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. C.

